Portsmouth's Defences and the Threat of Invasion in 1852

Throughout the 1850s and 60s there was a body of opinion in England that the French under their Emperor Napolean III was preparing to invade the nation. This culminated in the construction of a powerful defensive wall, in the form of sea and land forts around Portsmouth at enormous expense to the country. Known as Palmerston's Folly, the threat of invasion was real inasmuch these events sometimes occur without deliberate intent and the necessary factors for such an occasion certainly existed. As an early example of the panic being spread across the country we reprint below an article that appeared in the Hampshire Telegraph on December 11th 1852.

THE PERIL OF PORTSMOUTH
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FRENCH FLEET AND ENGLISH FORTS.

A pamphlet with, the above title, written by James Ferguson, Esq., and just published by Murray, of Albemarle Street, deserves the most serious attention not only of military men, but of the public also, especially at a time when our national defences are occupying so large a portion of public attention. Mr. Ferguson has always devoted himself to the study of fortification, and is the author of an "Essay on a proposed system of Fortification, with hints for its application to our National Defences" published in 1849; and of such importance was this essay deemed by Lieut. Col. Adams, Professor of Fortification at the Royal Military College at Sandhurst, that the Lieutenant Colonel delivered a lecture this season at the United Services Institution, wholely directed to its consideration. The Pamphlet just now presented, and before us, will be read with stirring interest throughout; we must, however, be content for the present with giving only the following extracts from it:-

SEA DEFENCES

There are two modes by which Portsmouth may be attacked - first, by a hostile fleet passing the batteries and entering the harbour; the second, by landing troops and storming the land defences.

The former is the one we shall consider first. It could scarcely be effected by sailing ships, it would require a strong leading southerly wind, which could largely be depended upon or obtained without the chance of waiting so long for it as to afford time for such preparations of defence being made as would render success extremely doubtful. Nor could it be affected by paddle-wheel steamers, as their broadside armament is so powerless; and the batteries are singularly well placed for hitting or disabling their paddles or those parts of their machinery necessarily above water. But it could be attempted by screw line-of-battle ships; and if I am not very much mistaken, with every prospect of success. The French now possess four such ships - the Napolean, the Charlemagne, the Austerlitz and the Jean Bart, and are understood to be building others. These vessels carry from 90 to 100 guns of the heaviest calibre, and though the speed of the Napolean is probably not so great as reported - thirteen to fifteen knots per hour - they are all equal to at least ten knots per hour in smooth water, and with a flood tide in the springs, both of which they could easily command.

At this rate of speed about ten minutes would elapse from the time when the first came within effective reach of the guns of Southsea Castle till they were safely passed all danger and anchored inside the harbour.

During one half of that time the only guns that could reach them are those of Southsea Castle; for the remainder they would be under the fire of the more formidable batteries of the town.

The question is, what damage could be done to them in this time? Let us follow the course of the leading ships a little more closely and perhaps we may be able to judge.

The first obstacle is Southsea Castle, within 600 yards of which the vessel must pass. This fortress was built by Henry VIII, and consists of a tall square tower or keep, of which three of four small guns are mounted; on each side of this is a semicircular wing carrying three or four more guns, looking over a weak and insignificant parapet; and outside the ditch there is one gun on the right flank, and three on the left - on traversing platform looking over an earthen glacis; these four being the only really effective guns in the fortress. As before stated, a vessel would be under fire of the Castle rather more than six minutes, but it is only when immediately in front, that more than half of its guns could be brought to bear on the vessel at any one time. If she were at anchor in front and attempt to play at long bowls with the fort, she might, it is true, receive some heavy blows; but she could afford to disregard the fire of four or five small guns till immediately opposite, when, approaching as near as soundings will permit, one broadside would probably finish the defences of Southsea Castle for ever. The guns, except four, being wholly surrounded by masonry of a very second-class order, the splinters would probably dismount every gun, even if it were not actually struck, and kill or wound the garrison to such an extent as would render it a very easy task for the second ship to complete what her consort had begun; for even the guns outside are jammed so closely to one another, that it is almost impossible they should escape.

Having passed this danger, the ship would next come within range of five guns mounted on the ravelin to the left of King's Bastion, and as many on a fleche to the right of it; the direction of the former is best, but it is distant; and as the ship need never come within 800 yards of it, every shot would not tell, and in less than three minutes it is shut out of view; while, owing to the confined space in which the guns are placed, a broadside would do it considerable damage. The fleche only sees the vessel, end on, till its embrasures prevent the guns seeing her at all.

The faces of the King's Bastion are singularly ill placed for batteries against shipping, and have only two guns mounted on them in consequence; but by far the most formidable of the defences in this quarter is the long curtain to the right of the King's Bastion; it now carries nine heavy guns on traversing platforms and behind earthen parapets; and if the uselss traverses were removed and the battery extended, it might mount 12 or 15; as it is, their direction is excellent, and, there being no masonry, a ship's broadside, though it might create dust, and dismount one or two guns, could not seriously damage such a battery, but it might create such a confusion as to enable the ship, going at ten knots, to pass without serious injury: this battery, however, is what she has most to fear; passing it, the platform battery, of course may be disregarded, and she then opens the new casemated battery on the Point; it mounts twelve formidable guns, but, being in casemates, their own smoke would prevent their being fired twice with anything like precision, at least during the time the vessel is within range, and before, or at least as soon as, the guns can see the ship, the ship's broadside could be poured into the battery; and though the embrasures are not funnel shaped, the destruction by splinters and the shot pouring into such a confined space would probably silence the batteries at once. Besides these, which would all see the ship's side there are four guns on the flank of the platform-battery, which would see her end on, six are in an orillion of the Point-battery in two tiers, and casemated, so as to render them nearly ineffectual, and twenty-four guns on the Blockhouse fort, likewise in two tiers, the lower casemated, with wide, gaping, funnel-shaped embrasures, the upper in masonry embrasures of equally bad shape but not casemated. None of these guns would ever see the side of the advancing ship, but only her stern, presenting, consequently a much smaller target to hit ; but on the other hand, she would be only able to reply from her bridle ports, so that the gunners would be tolerably free from molestation ; and if a shot did penetrate through the bows it might rake her fore and aft and do considerable damage. These batteries, however, being in two tiers, the smoke of the lower guns would prevent the upper from seeing what they were doing, and, being casemated, their own smoke would be a serious obstacle to quick and precise firing. Probably the best plan for a ship in such circumstances would be to close with her bridle-ports, coil her hemp cables in her bow, and stow there her hammocks and spare sails, in which case she would have little to fear from any of the guns ; and when she could, on turning into the harbour, pour her port broad-side into the Blockhouse fort, she would create such ruin as would render the work very easy for the ships which had to follow. Both the Blockhouse fort and Point batteries being mere casemated works of masonry, their effect in resisting the advance of a line-of-battle ship would not be more than if a fifty-gun frigate were moored where the former is placed, and a twenty-four gun corvette where the Point battery is : if they could stop four line-of-battle ships, so could these forts, but if they could not, the forts certainly would be unable to do so.

It is not, of course, contended that this would be an easy manoeuvre, or that the leading ship could enter the harbour without some very heavy blows, and many of her crew being killed or wounded ; but it is child's play in comparison with what ships have done before in action, and will do again : the time of action is so short that even the effect of hot shot is hardly to be feared ; and shells fired horizontally tell nearly equal on both sides of the question.

To put the question in another light. If Portsmouth were a foreign port, and a squadron composed of such ships as the Duke of Wellington, the Agamemnon, St. Jean d'Acre, Sans Pareil, were fitted out to force it, I would not ask such men as Lord Dundonald, Sir Charles Napier, and others, who have done far more desperate and daring things ; but I will undertake to say there are few admirals or officers in the British Navy who would not gladly volunteer to command or serve in such an expedition. Were it proposed, I fancy the Admiralty would be besieged with aspirants as it has seldom been besieged before ; and I believe there would be few things more acceptable to the French navy than to hear of their four vessels above named being ordered for the service sketched out above.

LAND DEFENCES.
As may be seen from the plan accompanying this, the works consist of three separate and distinct lines of fortification, the oldest being those of Portsmouth, the trace of which belongs to the age of Charles II, and William III, though somewhat improved since their days ; those of Portsea are of the time of George III, and very far superior both in trace and profile ; while those of Gosport are little better than field-works, consisting merely of an earthen rampart, unreveted, and without outworks, the only defence against even an attack "de vive force" being a shallow cunette of very miserable dimensions.

Estimating the strength of these lines, as is usual with engineers, by the number of days they resist a siege "en regle", from the first opening the trenches till the time when the besieger could certainly calculate on lodging himself on top of the breach, the Portsmouth lines may be estimated as capable of resisting from sixteen to twenty days, those of Portsea from twenty to twenty-four, and those of Gosport ten to twelve - that is, supposing everything to be clear in front and everything as favourable for the defender as for the besieger. This, however, is unfortunately far from being the case here, for the land in front of the lines not belonging to the Government has been built over all round, so that an enemy could approach on all sides, under cover, to the very foot of the glacis. This, on the Portsmouth side, would abridge the labour of the besieger probably four or five days; for though it may be said that the houses could be shot down from the ramparts, still their rubbish would afford the required cover and supply timber for battery platforms, blindages, &c., which would facilitate matters amazingly; and on the Gosport side it is fatal, for an enemy finding cover within easy musket range of works is liable to be carried by a "coup de main" would probably settle the matter in four-and-twenty hours, and even if it was deemed necessary to proceed with more caution seven days ought to suffice to insure success against these lines.

A fleet sufficiently powerful to subdue any resistance it might find from ships at Spithead may take up any position it chooses between Cowes and Ryde, without one single gun being brought to bear on it, either in taking up its position or when at anchor; and may then with the certainty of smooth water, land its troops anywhere it pleases between Stokes Bay and Southampton.

Once landed, the first operation I conceive would be to occupy Fareham and throw up a series of lines from the harbour to the Solent, probably at Hillhead Haven : this done, and their left secure, their front being covered by the harbour, their rear by the sea and their fleet, they are at liberty to pursue operation against Gosport at leisure. As I said before, I feel convinced that such troops as the Chasseurs de Vincennes would carry the place at a rush, and, if there was so such hurry, by siege in a week or ten days. Once in possession of Gosport, the dockyard and both towns are perfectly open ; the harbour, and all that it contain, may be destroyed ; the Blockhouse fort, housing only a tall brick wall to oppose, may easily he rendered untenable, and the other town batteries looking towards the outer harbour enfiladed or destroyed, so that the road is open for the fleet or its boats to enter and take possession when it suits their convenience, but there would be no hurry; as a defensive element Portsmouth would be destroyed, and its actual possession to an enemy carefully entrenched on the Gosport peninsula of singularly little importance.

INVASION OF ENGLAND.
The mode of attack probably would be for the whole invading force to pass through Spithead, land 20,000 or 30,000 troops between Stokes Bay and Southampton Water, and, while these attacked by land, for the Screw line of battle ships to force the harbour. As at present fortified Portsmouth could not resist such a combined attack for a single hour, and, once in possession of it, 20,000 Frenchmen would soon strengthen the existing Hilsea lines, and throw up a range of defences between Brown Down and the harbour, probably on the very ground I have marked out ; and imperfect as these hurried works must necessarily be, 20,000 or 30,000 good troops would easily hold them against anything we could bring against them ; and safely encamped in this position, and with their steamers bringing over 10,000 or 20,000 additional troops per diem, the invasion of England is accomplished ; the holding it as a conquered country is another matter ; but once firmly fixed on an impregnable position on our Shores, the fall of the capital is inevitable.

One word in conclusion. Many will say, why publish our weaknesses and lay bare to the stranger the nakedness of the land? If it could be concealed I should be the last to reveal it. But I have no special sources of information ; what I have seen or know every foreigner may see and know, and, what is more, does know, and knows perfectly. There is not a department in the French army or navy that has not access to perfect plans of all our dockyards and fortifications ; they know every gun that is mounted or laid aside, they know the exact number of our garrisons, and watch with the keenest interest the movements of our fleet ; and not only at headquarters but in every mess-room, the feasibility and means of attacking England are warmly and keenly discussed ; there is not a well-informed officer in either branch of the service that has not made up his mind on most of the points connected with this subject, or who is not prepared how to act, or what to advise, if called upon. There are, and can be, no secrets in the matter; and while this is the ease, it is not by shutting our eyes, or, like pheasants, putting our heads under a stone, that we shall avoid the danger, but by looking it in the face like men, and meeting it boldly and effectually, which we are easily able to do, and do in a manner which can offend no one.

If we increase our army or navy we give a feasible pretext for others to do so likewise, for ships and soldiers are means of aggression as well as of defence.